ASSESSMENT OF CYTOTOXICITY, ANTIOXIDANT AND FREE RADICAL SCAVENGING ACTIVITIES OF THE ETHYLACETATE EXTRACT OF CALLIANDRA PORTORICENSIS ROOT BARK

Calliandra portoricensis a medicinal plant, is widely use in the treatment/management of various diseases in Nigeria. The ethyl acetate extract of the Calliandra portoricensis root bark were tested to evaluate the cytotoxicity, antioxidant (in vitro) and free radical scavenging activity. The different assay methods, including total antioxidant activity, free radical (nitric oxide, hydroxyl radicals and lipid peroxidation) scavenging assays were used to evaluate the antioxidant potential of the ethylacetate extract. While cytotoxic activities were evaluated using brine shrimps lethality assays. The methanol extract showed total antioxidant capacity of 2.362µg/mg of plant extract expressed as ascorbic acid equivalents (AAE) compared to 1µg/mg ascorbic acid; the extract exhibited two-fold scavenging activity with IC₅₀ of 364.175 and 313.52µg/ml for nitric oxide and hydroxyl radicals compared to IC₅₀ of 231.31µg/ml and 228.78µg/ml of ascorbic acid as standard respectively. The extract conferred 50% protection at the concentration of 51.92μg/ml on lipid peroxidation induced by FeSO₄ in liver mitochondria. The Brine shrimp lethality bioassay of the extract showed cytotoxic activity of (LC₅₀ = 0μg/ml) which falls within 0-100μg/ml considered to be lethal. In conclusion, the study clearly indicated that the ethyl acetate extract of Calliandra portoricensis root bark possesses potent bioactive compounds, good antioxidant and free radical scavenging activity along with moderate toxicity which can be harness and purified into useful therapeutic drugs.